turnip vs Brassica rapa

turnip and Brassica rapa both are nouns.

Word	Noun	Adjective	Verb	Adverb
turnip	Yes	No	No	No
Brassica rapa	Yes	No	No	No

As nouns, turnip and Brassica rapa are synonyms defined as:

turnip and Brassica rapa: widely cultivated plant having a large fleshy edible white or yellow root

Other synonyms of turnip include white turnip.

turnip (noun)	Brassica rapa (noun)
root of any of several members of the mustard family	widely cultivated plant having a large fleshy edible white or yellow root
widely cultivated plant having a large fleshy edible white or yellow root